r600g: Fix the PIPE_FORMAT_L8A8_UNORM color swaps.

src/gallium/drivers/r600/eg_state_inlines.h

@@ -312,6 +312,7 @@ static inline uint32_t r600_translate_colorswap(enum pipe_format format)
 		return V_028C70_SWAP_STD;
 
 	case PIPE_FORMAT_L8A8_UNORM:
+		return V_028C70_SWAP_ALT;
 	case PIPE_FORMAT_R8G8_UNORM:
 		return V_028C70_SWAP_STD;
 

src/gallium/drivers/r600/r600_state_inlines.h

@@ -305,6 +305,7 @@ static inline uint32_t r600_translate_colorswap(enum pipe_format format)
 		return V_0280A0_SWAP_STD;
 
 	case PIPE_FORMAT_L8A8_UNORM:
+		return V_0280A0_SWAP_ALT;
 	case PIPE_FORMAT_R8G8_UNORM:
 		return V_0280A0_SWAP_STD;